Typically, mobile communication systems have been developed for the purpose of providing communication while ensuring mobility of users. Due to the rapid development of technologies, the mobile communication systems have reached a stage capable of providing high-speed data communication services as well as voice communication services. Recently, the next-generation mobile communication systems have evolved into Human to Machine (H2M) communication and Machine to Machine (M2M) communication, beyond Human to Human (H2H) communication. In order to meet such a requirement, the 3rd Generation Partnership Project (3GPP), which is responsible for the standardization of communication, is working on a standard for machine-type communication. In a 3GPP System Aspects Working Group 1 (SA1) Working Group (WG) standard, which defines services and the characteristics thereof, service requirements for machine-type communication is already being discussed.
FIG. 1 illustrates a communication scenario in machine-type communication. Machine-type communication devices 105 are connected to a wireless operator's network 110. The machine-type communication devices 105 may be typically defined as various unmanned devices such as meters, vending machines, or the like, and have characteristics different in many aspects from those of the existing wireless terminals. Also, the characteristics of the machine-type communication devices 105 may depend on the types thereof. One cell may include numerous machine-type communication devices 105 which have the various characteristics as described above. A machine-type communication server 115, which has information on the machine-type communication devices 105, may serve not only to perform authentication, but also to collect pieces of information acquired from the machine-type communication devices 105 and to deliver the collected pieces of information to a machine-type communication user 120. The machine-type communication server 115 may exist inside or outside the wireless operator's network. The machine-type communication user 120 is an end user that requires information delivered by the machine-type communication devices 105.
The machine-type communication has characteristics different from those of the existing wireless communication. Also, the characteristics of the machine-type communication may be very variously classified according to use purposes thereof. For example, machine-type communication devices, which require communication only a few times a day regardless of time, have a time-tolerant characteristic, and machine-type communication devices, which are installed at fixed positions and serve to collect and transmit particular information without mobility, have a low mobility characteristic. Wireless operators need to provide services in view of such various characteristics of the machine-type communication and the coexistence of machine-type communication devices with the existing terminals.
Among the machine-type communication devices, tracking-related devices, such as devices equipped on animals or cargo vehicles, typically use batteries, or are supplied with power generated by themselves. Accordingly, since the machine-type communication devices need to use limited power, and it is desirable that the machine-type communication devices efficiently use extremely small power. The 3GPP SA1 WG defines an extra low power consumption mode, in which machine-type communication devices may be configured to be able to use low power. In this situation, there is a need for a method and an apparatus for transmitting and receiving signals to/from the machine-type communication devices.